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Record-setting wet August for some, first frosts in the north

Record-setting wet August for some:

Over 40 climate observers across the state report over 6.5 inches of rainfall for this month, roughly twice the normal amount. With a week to go these numbers will certainly increase. For some locations it has already been a record-setting wet month. This is true for the following locations:
Redwood Falls (Redwood County) 13.03 inches Granite Falls (Yellow Medicine County) 11.09 inches
Montevideo (Chippewa County) 10.43 inches
Hawley (Clay County) 10.43 inches
Bird Island (Renville County) 10.41 inches
Vesta (Redwood County) 9.62 inches

In addition over 60 new daily rainfall records have been set this month within the Minnesota climate observation network.

First freezing temperatures this month:

On Thursday morning, August 24th, this week the first sub-freezing temperatures were reported with a 32°F reading at Isabella (Lake County), and just 30°F at Crane Lake and Embarrrass (St Louis County). At least 8 other climate stations reported morning lows in the 30s that morning. The readings of 30 degrees F at Embarrass and Crane Lake on August 24th was their first sub-freezing temperature since June 1st, while at Isabella, the 32 degrees F was the first frost since May 19th. It is not unusual to have frost at these locations during the month of August, and more temperature readings in the 30s F (such as occurred again Friday morning) are likely to occur in northern areas later this month.

State Fair time:

The Annual Minnesota State Fair will began Thursday, August 24th and runs through Labor Day, September 4th. It appears that the beginning days of the Fair will be cooler than normal temperatures, perhaps just in the 60s and 70s F. Also there are chances for repeated shower activity over the Friday through Sunday period, then drier next week. I will be at the MPR Booth (corner of Judson and Nelson on the fairgrounds) on two dates: Friday, August 25th at noon to record the TPT Almanac public affairs program with hosts Cathy Wurzer and Eric Eskola; and then again on August 29 (Tue) with host Tom Weber at 11am to broadcast the annual Minnesota Weather Quiz. Please stop by if you are at the Fair either of those days.

Weekly Weather Potpourri:

The NOAA National Hurricane Center was issuing warnings on Hurricane Harvey this week in the Gulf of Mexico. Harvey was expected to strengthen and produce sustained winds up to 120 mph, with higher gusts as it approached the coastline of Texas (around Corpus Christi and northeast to Sargent). Storm surge estimates range from 6 to 12 feet, and rainfall estimates typically range from 15 to 25 inches for this storm. In the Western Pacific Ocean Tropical Storm Pakhar was approaching the Philippines and is expected to bring heavy rains and high seas there for Friday and Saturday.

This week the New York Times published a well-documented study of the loss of permafrost in the state of Alaska. The pace of loss is greatly accelerated in the context of historical climate behavior, and concern is expressed over the amount of carbon that will be released in the thawing of vast amounts of permafrost in the Alaska landscape over the next century.

This week marked the 150th Anniversary of the birth of the iconic "Shipping Forecast" in the United Kingdom, founded by the famous Vice-Admiral Robert FitzRoy who captained the HMS Beagle during Charles Darwin's expedition. The Shipping Forecast is one of the most widely listened to broadcasts on the BBC. The UK Met Office and BBC posted interesting story about this.

Scientists from the University of Copenhagen reported this week from a study of Lake Catalina in East Greenland that using satellite data they have found evidence of four huge outburst floods over the past 50 years, each of which released over a half and up to one cubic mile volume of fresh water into a fjord.

MPR listener question:

I heard you talk to Cathy last week about Redwood Falls having its wettest August in history this year. Isn't August also the month with the most rainfall in history for Minnesota? I want to say this happened in 2007.

Answer:

For an individual location you are right. The all-time state record is 23.86 inches at Hokah (Houston County) in 2007. But on a statewide basis, August has not been our wettest month. Our wettest month on a statewide basis was June 2014 when the average rainfall from all observations across the state was 8.07 inches. List below are the top ten wettest months in history based on the statewide average rainfall reported from all climate stations.

(1) June 2014 8.07”

(2) Tie between July 1897 and June 1914 7.32”

(3) June 1905 6.83”

(4) August 1900 6.80”

(5) June 1915 6.72”

(6) June 1984 6.68”

(7) June 1957 6.67”

(8) June 1925 6.65”

(9) June 1944 6.54”(10)September 2010 6.41”

Twin Cities Almanac for August 25th:

The average MSP high temperature for this date is 79 degrees F (plus or minus 8 degrees F standard deviation), while the average low is 61 degrees F (plus or minus 6 degrees F standard deviation).

Average dew point for August 25th is 58°F; the maximum dew point on this date is 75°F in 1990; and the minimum dew point on this date is 26°F in 1934.

All-time state records for August 25th:

The all-time state high temperature for today's date is 102 degrees F at St Vincent (Kittson County) in 1886; the all-time state low for today's date is 25 degrees F at Littlefork (Koochiching County) in 1915. The all-time state record precipitation for this date is 5.08 inches at Pokegama Dam (Itasca County) in 1941. No snow has fallen on this date.

Past Weather Features:

Hot weather prevailed across the state on August 25, 1886. Most areas saw afternoon temperatures climb to 90°F plus, while portions of the Red River Valley recorded afternoon highs of 100 degrees F or greater.

Spectacular northern lights were observed across the sky all over the state of Minnesota on August 25, 1916 from 8pm to midnight. The aurora was so brilliant it was even visible for Twin City’s residents, rare indeed and almost unheard of today.

August 25th in 1917 was a cold one. Five communities in northern Minnesota reported frosts, while a number of communities reported daytime high temperatures that only reached the 60s F, and with a cool northwest wind felt even colder.

A system of organized thunderstorms known as a "derecho" crossed the state over August 25-26, 1990 producing heavy rains and strong winds, estimated at 70 to 80 mph. Many observers reported rains of 3-6 inches which produced widespread flash flooding. The strong winds damaged many farm buildings and caused power outages across Douglas, Grant, Wilkin, Big Stone, and Otter Tail Counties in western sections of the state.

The hottest August 25 in the modern era was in 2013 when over 100 communities reported afternoon temperatures in the 90s F. The afternoon Heat Index surpassed 100 degrees F at a number of locations. The nighttime temperatures were warm too, not falling below 75 degrees F at over 30 locations.

Outlook:

A cloudy weekend coming up with chances for showers and thunderstorms each day. Cooler than normal temperatures will prevail through the weekend. Drier weather on Monday, then a warming trend begins on Tuesday, with a drier pattern in place for much of next week.